Blue Jay

The Blue Jay measures 22–30 cm (9–12 in) from bill to tail and weighs 70–100 g (2.5–3.5 oz), with a wingspan of 34–43 cm (13–17 in).There is a pronounced crest on the head, a crown of feathers, which may be raised or lowered according to the bird's mood. When excited or aggressive, the crest may be fully raised. When frightened, the crest bristles outwards, brushlike. When the bird is feeding among other jays or resting, the crest is flattened to the head.

Its plumage is lavender-blue to mid-blue in the crest, back, wings, and tail, and its face is white. The underside is off-white and the neck is collared with black which extends to the sides of the head. The wing primaries and tail are strongly barred with black, sky-blue and white. The bill, legs, and eyes are all black. Males and females are nearly identical.

As with most other blue-hued birds, the Blue Jay's coloration is not derived from pigments but is the result of light interference due to the internal structure of the feathers; if a blue feather is crushed, the blue disappears as the structure is destroyed. This is referred to as structural coloration.

Cockatiel

The Cockatiel (Nymphicus hollandicus), also known as the Quarrion and the Weiro, is a member of the cockatoo family endemic to Australia. They are prized as a household pet and companion parrot throughout the world and are relatively easy to breed. As a caged bird, cockatiels are second in popularity only to the Budgerigar.

The cockatiel is the only member of the genus Nymphicus. It was previously considered a crested parrot or small cockatoo; however, more recent molecular studies have assigned it to its own unique Cockatoo subfamily Nymphicinae. It is, therefore, now classified as the smallest of the Cacatuidae (Cockatoo family). Cockatiels are native to Australia, and favour the Australian wetlands, scrublands, and bush lands.
Data refer: http://en.wikipedia.org/wiki/Cockatiel

Sun Conure

On average, Sun Parakeets weigh approximately 110 g (4 oz) and are around 30 cm (12 in) long.They are sexually monomorphic.

Adults have a rich yellow crown, nape, mantle, lesser wing-coverts, tips of the greater wing-coverts, chest, and underwing-coverts. The face and belly are orange with red around the ears. The base of the greater wing-coverts, tertials, and base of the primaries are green, while the secondaries, tips of the primaries, and most of the primary coverts are dark blue. The tail is olive-green with a blue tip. From below, all the flight feathers are dark greyish. The bill is black. The legs and the bare eye-ring are grey, but the latter often fades to white in captivity (so using amount of grey or white in the eye-ring for determining "purity" of an individual can be misleading). It is easily confused with the closely related Jandaya Parakeet and Sulphur-breasted Parakeet, but the former has entirely green wing-coverts, mantle and vent, while the latter has green mottling to the mantle and less orange to the underparts. The Sun Parakeet is also superficially similar to the pale-billed Golden Parakeet.

Juvenile Sun Parakeets display a predominantly green plumage and resemble similar-aged Sulphur-breasted Parakeets. The distinctive yellow, orange, and reddish colouration on the back, abdomen, and head is attained with maturity.
Data refer: http://en.wikipedia.org/wiki/Sun_Conure